Guide · Residential · Granny flats
2 bedroom granny flat designs that fit real Perth blocks.
Three layouts, what each one is good at, and the R-Codes limits that decide which will actually fit on your lot.
GPD Group · WA Builder Licence BC104702 · Updated 2026
Two bedrooms is the point where a granny flat stops being a studio and starts being a home. It is also the point where the layout matters more than the finishes, because you are fitting two private rooms, a bathroom, a kitchen and a living space into an envelope your council has already capped.
The three 2 bedroom granny flat designs below are the layouts that come up most often on Perth blocks. Each one solves a different problem, and the right answer depends far more on your lot than on your taste.
Short answer
Most Perth councils allow ancillary dwellings up to 70 square metres of internal floor area, with recent WA reforms permitting up to 120 square metres in some local government areas. Two bedrooms fit comfortably at 60 to 70 square metres if the living space is planned first and the corridors are planned last.
Design 01
Open-plan living, two bedrooms off one hall.
The default and the most forgiving. A single open kitchen, dining and living zone runs across the front, with both bedrooms and the bathroom pushed to the rear off a short hall.
Why it works
One continuous space makes 70 square metres read as far larger than the number suggests. Circulation happens through the living zone rather than through a corridor, which is floor area you would otherwise be paying for and never using.
Where it struggles
Noise. With bedrooms opening off a shared hall next to the living space, a late television and an early shift do not coexist well. Worth specifying acoustic insulation in the bedroom walls at design stage rather than regretting it later.
Best suited to
Rental, adult children, or anyone who wants the dwelling to feel like a small home rather than a subdivided box.
Floor plan · Design 01
Open-plan, bedrooms off one hall
LIVING
KITCHEN
BED 1
BED 2
BATH
HALL
ONE CONTINUOUS ZONE
Circulation happens through the living zone rather than a corridor, so the hall stays short. Amber marks glazing. Specify acoustic insulation in the bedroom walls, because both open off the same hall beside the living space.
Design 02
Maximising small blocks: the narrow rectangle.
Where side setbacks and existing site coverage leave you a long, thin footprint, the layout runs in a line: living at one end, bathroom central, bedrooms at the other.
Why it works
It fits where nothing else does. On a lot where the main dwelling already covers most of the permitted site coverage, a narrow footprint is often the only compliant option. Services run in a straight line too, which keeps plumbing and electrical costs down.
Where it struggles
Light. A narrow plan with windows only at the ends leaves the middle dark, so the bathroom and hall need either skylights or borrowed light designed in from the start.
Best suited to
Constrained inner-suburb lots, and blocks where the existing house and its parking already dominate the site.
Floor plan · Design 02
Narrow rectangle for a constrained lot
LIVING
KITCHEN
BATH
BED 1
BED 2
CIRCLE MARKS A SKYLIGHT: THE CENTRE HAS NO EXTERNAL WALL FOR GLAZING
Services run in a straight line, which keeps plumbing and electrical cost down. The weakness is light: with windows only at the ends, the bathroom and hall need skylights or borrowed light designed in from the start.
Design 03
The entertainer’s layout: living opens outward.
Living and kitchen open through wide glazing onto a deck or paved alfresco area, with the two bedrooms tucked behind. The outdoor space is treated as a room rather than as leftover yard.
Why it works
The usable area is larger than the internal area, which matters when the code caps what you can build under a roof. A covered alfresco can extend a 70 square metre dwelling into something that lives like 90.
Where it struggles
Cost and privacy. Wide glazing carries an energy rating penalty that has to be offset elsewhere, and opening the living space outward means thinking hard about sightlines back to the main house.
Best suited to
Multi-generational use, and blocks with a genuinely usable orientation to the north or east.
Floor plan · Design 03
Entertainer, living opens outward
BED 1
BED 2
BATH
LIVING
KITCHEN
COVERED DECK
USABLE AREA OUTSIDE THE INTERNAL FLOOR-AREA CAP
The deck sits outside the internal area the code caps, so a 70 square metre dwelling can live like 90. The trade is glazing cost and privacy: opening the living space outward means thinking hard about sightlines back to the main house.
About these plans
Schematic only, drawn to show room relationships rather than dimensions. Every one of these gets redrawn against your actual lot, because setbacks, site coverage and the position of the existing dwelling decide what fits before a designer draws anything.
Compared
How the three 2 bedroom granny flat designs compare.
No layout wins outright. Read this against your block rather than against your preference.
All three sit inside GPD’s standard granny flat band of $140,000 to $220,000 for a 60 to 70 square metre new build. The layout affects the price far less than the specification does, which surprises most people.
Tips
Maximising space and natural light.
All three 2 bedroom granny flat designs benefit from the same five decisions, none of which cost much when they are made at design stage.
Plan the corridors last
Every square metre of hallway is a square metre you cannot furnish. Position rooms so circulation passes through space you are already using.
Orientation before window size
North-facing living glass does more for light and warmth than a larger west-facing window, and it does not punish your energy rating in the process.
Ceiling height is cheap volume
Raising the ceiling adds perceived space for a fraction of what adding floor area costs, and floor area is what the code limits.
Build storage into the structure
Recessed robes, a linen niche and under-bench storage cost less than the floor area a freestanding wardrobe consumes.
Solve the energy rating early
The 7-star NatHERS standard applies to ancillary dwellings. Insulation, glazing and orientation are cheap to specify at design and expensive to retrofit at quote stage.
Worth knowing
Councils typically require one additional parking bay for an ancillary dwelling, and that bay competes with your outdoor space. Settle where it goes before the layout is locked, not after.
Next step
All three 2 bedroom granny flat designs are quoted the same way. Our granny flats Perth page covers the four delivery paths, the R-Codes rules that decide what fits on your lot, and the full approvals process. For a larger build, see new home builds.
Find out which layout your block will carry.
Send the suburb and the lot and we will tell you what the R-Codes allow before anyone draws anything. The builder reads every brief himself and replies inside one business day.
GPD Group · WA Licence BC104702 · ABN 22 668 388 056 · info@gpdgroup.org
